Old Make Installs: Linker Order

-lpng has to be linked after -lpngwriter since pngwriter
will leave open symbols to libpng that have to be filled
up afterwards.

Use the CMake based install ;)
Close #28 CMake Builds Test by Default

One could alternatively add an additional target but since
neither the examples nor tests should be installed afterwards
that should be fine.
Merge pull request #35 from ax3l/topic-buildUpdates

Build Updates: Fix Linker Order and Tests